This sounds like a great idea but there's a potential drawback: It would be shame if a lot of old chestnut problems that are great the first time you encounter them were listed with their answers easy to find, so that newcomers to these problems might be too tempted to just look up the answer instead of working on them. (Or does Google already make this the case?) --Dan Rich wrote: << While we're on the subject of math-related databases, I'll mention another collection we need: Worked Problems & Puzzles. Mathists generate and solve a lot of problems. Most of these are not profound enough to publish. It would still be worthwhile to collect them, to smooth the path for followers. Collecting is the easy part; the hard task is organization & making it searchable. For example, some of the geometry problems we've discussed over the years: How to make them searchable beyond adding keywords? Searching for "ellipse intersection" is too unspecific.

...

Sometimes the brain has a mind of its own.